Self-cleaning oven

ABSTRACT

A self-cleaning oven with front door means and having inner and outer walls spaced in insulating relationship to each other and defining air passages at the rear, bottom and sides of the oven, with control means disposed in a side passage, air ducts in the lower ends of the side passages with apertures in their top walls and terminating adjacent the bottom of the front door means, and blower means comprising an inner fan disposed interiorly of the oven for circulating heated air therein, an outer fan in the rear air passage, and a motor exteriorly of the oven mounted coaxially with the fans, with shroud means spaced from the motor to insure movement through and around the motor of outside air drawn inwardly by the outer fan and blow thereby over the control and front door means for cooling purposes, plate and spacer means interconnecting the two fans to prevent direct transfer of heat from the inner fan to the motor, improved front door operating mechanism, and temperature-responsive door locking means automatically operable during a cleaning cycle.

United States Patent Anetsberger et al.

[54] SELF-CLEANING OVEN [72] inventors: Richard J. Anetsberger; John A. Anetsberger, both of Northbrook, lll.

[73] Assignee: Anetsberger Brothers, Inc.,

Y Northbrook, ill.

[22] Filed: Dec. 16, 1970 [21] Appl. No.: 98,694

[52] U.S. Cl. ..126/21 A, 126/197, 126/273 R [51] Int. Cl. ..F24c 15/32 [58] Field of Search.....l26/2l R, 21 A, 19 R, 273 R, 126/39 C, 197

[5 6] References Cited UNITED STATES PATENTS 3,081,392 3/1963 Warner ..126/21 A X 2,525,614 10/1950 Nelson et al.... ..l26/2l A X 3,512,514 5/1970 Vonasch ..126/21 A 3,463,138 8/1969 Lotter et al ....l26/21 A 3,529,582 9/1970 Hurko et a1 ..l26/21 A [451 Dec;26, 1972 Primary Examiner-Charles .l. Myhre Attorney-Davis, Lucas, Brewer & Brugman [57] ABSTRACT A self-cleaning oven with front door means and having inner and outer walls spaced in insulating relationship .to each other and defining air passages at the rear,

bottom and sides of the oven, with control means disposed in a side passage, air ducts in the lower ends of the side passages with apertures in their top walls and terminating adjacent the bottom of the front door means, and blower means comprising an inner fan disposed interiorly of the oven for circulating heated air therein, an outer fan in the rear air passage, and a motor exteriorly of the oven mounted coaxially with the fans, with shroud means spaced from the motor to insure movement through and around the motor of outside air drawn inwardly by the outer fan and blow thereby over the control and front door means for cooling purposes, plate and spacer means interconnecting the two fans to prevent direct transfer of heat from the inner fan to the motor, improved from door 1 operating mechanism, and temperature-responsive door locking means automatically operable during a cleaning cycle.

9 Claims, 8 Drawing Figures PATENTED DEC 2 6 I972 SHEET. 3 OF 3 w M M SELF-CLEANING OVEN BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates generally to food cooking equipment, and more particularly to ovens.

2. Description of the Prior Art Self-cleaning ovens are known which employ inner and outer walls spaced from each other in insulating relationship and control means for selectively maintaining the ovens at desired cooking temperatures, as from 150 to 550 F., and cleaning temperatures between 750 and 950 F.,-and include blower or fan means interiorly-of the oven for circulating the heated air therein. And coaxially mounted fans driven'by a single motor are shown in US. Pat. No. 3,437,085, but the outer fan therein is used to supply primary and secondary air for the gas burner means employed. A primary difficulty with such self-cleaning ovens is that the control means, the fan motor and the front door means are seriously adversely affected by the excessive heat generated during a cleaning cycle. And where interengaging front doors are employed, difficulties are encountered therewith during a cleaning cycle.

SUMMARY OF THE INVENTION This invention provides means in a self-cleaning oven for effectively cooling the front door means, control means and motor, which is of particular importance during a cleaning cycle and materially increases the life of the motor and control means. These novel results are accomplished by placing cool air ducts in the rear, bottom and side wall spaces of the oven terminating adjacent the bottom of the front door means and with apertures communicating with the side wall spaces, mounting the control means in one of the latter, and providing an outer cooling air circulating fan coaxial with the usual inner fan and disposed in the rear wall space and connected to the fan motor which is mounted exteriorly of the oven, with a shroud spaced from the motor to require cooling air drawn in by that outer fan to pass over the motor, and an imperforate plate mounted on the outer end of the inner fan to drivingly support the inner fan on the outer fan while preventing direct heat transmission from the inner fan to the motor shaft. Novel front door means also are provided which overcome operating difficulties due to the extreme heat during a cleaning cycle and are automatically locked closed when the oven temperature is higher than normal maximum cooking temperature.

In the Drawings:

FIG. 1 is a perspective view of an oven embodying the features of the invention;

FIG. 2 is an end elevational view, as seen from the right side of FIG. 1;

FIG. 3 is a detail vertical section through the blower means;

FIG. 4 is a horizontal sectional view taken substantially on the line 44 of FIG. 1;

FIG. 5 is a vertical section taken substantially on the line 5-5 of FIG. 2;

FIG. 6 is a detail perspective view of the lower front portion of the oven with the door operating and locking means exposed;

FIG. 7 is a detail horizontal section taken substantially on the line 7-7 of FIG. 6; and

FIG. 8 is a detail horizontal section taken substantially on the line 88 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT 0 and inner top walls 12 and 13, outer and inner side walls 14 and 15, outer and inner rear walls 16 and 17, outer and inner bottom walls 18 and 19 and a front portion including front doors 21 and a transversely extending manifold 22 disposed therebelow. As is customary in such double-walled constructions, this provides interconnected rear, bottom and side wall spaces. Horizontal cooling air ducts 23 are disposed in and along the lower ends of the side wall spaces which are open at their front and rear ends and provided in their top walls with spaced apertures 24. The manifold 22 is open at its inner lower portion to communication with the open front ends of the ducts 23 and is provided in its top edge with a plurality of apertures 24 '(FIGS. 1 and 2) like those in the top walls of ducts 23 through which cooling air will be directed in a manner later to be described.

At its right-hand forward corner, the oven 11 is provided with a hollow vertically extending column 25 within which the usual several control means 26 are mounted with their manually operable elements extending forwardly through suitable apertures in the column for convenient actuation by an operator. The bottom of this column 25 andthe adjacent portion of the right-hand duct 23 are provided with a plurality of interconnecting apertures 27 (FIGS. 2 and 4), and the column 25 similarly communicates at its upper end with the space between the top walls 12 and 13. As seen in FIG. 4, the front end of the right-hand duct 23 has an inwardly directed extension for communication with the open bottom portion of the manifold 22. The outer rear wall 16 is provided with air outlet means in the form of apertures 28 (FIG. 1) at the uPPer corner portions thereof. As best seen in FIG. 5, the outer bottom wall structure 18 is provided with angularly disposed baffles or deflector portions 29 extending from front to rear of the oven for protecting the the side cool air ducts 23 from heat from the burner means 30 and deflecting heat rays from the latter upwardly against the inner bottom wall 19. The burner means 30 is disposed in well-known manner in the bottom space between the walls 18 and 19, and it will be understood that either gas or electricity may be used as the energy source. 1

Blower means, indicated generally by reference numeral 31, are mounted at the rear of the oven 1 1 for the dual purpose of circulating heated air within the oven proper, as defined by the inner walls 13, 15, 17 and 19 and the front door means 21, and forcing cooling air from the outside, over the motor employed, through the wall spaces, and particularly over the control means 26 and the outer surfaces of the door means 21. As best seen in FIG. 3, this blower means 31 may be secured in position in a suitable aperture in the inner rear wall 17 by means of a mounting plate 32 and nuts and bolts 33.

An air duct 34, the upper portion of which is substantially cylindrical, has its inner wall secured by suitable nuts and bolts 35 to the mounting plate 32, with a gasket of appropriate insulating material 36 disposed therebetween. The rear wall of this air duct 34 has a circular inlet aperture 37, and a motor 38 is secured to the air duct by means of suitable bolts and nuts 39 spaced around and adjacent to the periphery of the aperture 37 and having spacing washers 41 thereon to substantially align the motor base with the outer rear wall 16, the latter being provided with an air inlet aperture 42 surrounding and spaced from the motor base.

Mounted upon and secured in any suitable-manner to the shaft of the motor 38 is the hub 43 of a cooling fan 44 which is disposed within the cylindrical portion of the air duct 34. An imperforate circular plate 45 is secured to the inner end of the cooling fan 44 by bolt and nut means 46 and spacers 47, and mounted upon the inner surface of the plate 45, PF ferably by the bolt and nut'means 46, is an inner fan 48 which is coaxial with the cooling fan 44. It will be noted from HO. 3

that the imperforate plate 45 substantially fills the apertures 49 which coincide with each other and extend through the mounting plate 32, insulating gasket 36 and inner wall of the air duct 34.

in order to require ambient air drawn in by the cooling fan 44 to pass over and in close proximity to the motor 38 to cool the same, a shroud means in the form of a cylindrical casing 51 is mounted in any suitable manner on the outer rear wall 16 surrounding the inlet aperture 42, being provided in its outer wall with a circular air inlet aperture 52. Air drawnin through this aperture 52 by the cooling fan 44 will pass over the motor 38 and into the air duct 34 through its inlet aperture 37. The air duct 34 has a discharge outlet 53 (FIG.

3) which is vertically aligned with the upper end of a duct extension 54 extending therefrom downwardly throughthe rear wall space and separating into two lateral branches for communication at their lower ends, respectively, with the rear ends of the ducts 23. For distributingly guiding the air from the branches 54 into the ducts 23, suitable deflector plates 55 are provided, as best seen in FIGS. 1 and 4.

Cooling air drawn in over the motor 38 by the fan 44 thus will be directed from the lower ends of the duct extension 54 into the side ducts 23, the side wall spaces through the apertures 24, and the control column 25 through the apertures 27. Some of this cooling air also will be directed into the manifold 22 and upwardly over the front surfaces of the door means 21, while part of it will effectively dissipate heat from the several control means 26, and that portion of the cooling air not directed over the front doors will be discharged rearwardly from the oven through the apertures 28. The net result is the accomplishment of the objectives initially noted herein to make practical the self-cleaning of the oven by means of temperatures between 750 and 950 F. by effectively cooling the exterior of the oven and, most importantly, the control means 26 and the motor 38. The novel mounting of the inner fan 48 by means of the imperforate plate 45 and spacers 47 performs the function of preventing direct transfer of heat to the shaft of motor 38. This is particularly important.

because the fan 48 is subjected directly to maximum heat and the direct transfer of that heat to the shaft of the motor has been found to cause rapid deterioration of the motor. And the shroud 51 also helps to insure normal life for the motor despite frequent high temperature oven self-cleaning operations.

The front door means for the oven 11, as previously noted, comprises a pair of doors 21 interengaging with each other in the usual manner, as by means of a sealing edge flange at the rear and along the inner edge of the right-hand door, and manual means are provided for opening and closing the doors which include a han die 56 secured to and extending forwardly from the inner portion of the left-hand door 21. Each door 21 is mounted for swinging movement by means of a pintle S7 vertically disposed adjacent its outer edge which is rotatably supported in any suitable manner. A sprocket wheel 58 is mounted on each of the pintles 57 adjacent the lower ends thereof and a chain segment 59 passes around and engages each of the sprockets 58 (FIG. 6). The forward portion of the left-hand chain segment 59 is connected to the rear portion of the right-hand chain segment 59 by means of an adjustable solid linkage comprising an outer link 61 and an inner link 62 adjustably interconnected by suitable bolt means 63 (H6. 7). A plate or bracket 64 is secured in any suitable manner at its upper end to the inner link 62, with the lower end of that bracket connected to the frame of the oven by a spring 65 (P16. 6). The forward end of the right-hand chain segment 59 likewise is connected to the rear end of the left-hand segment 59 by a similar adjustable solid linkage 61-63 which also includes a depending bracket 64 and a spring 65 connecting the lower end of that plate to the frame of the oven. With this arrangement, means are provided thereby for swinging the right-hand or second door 21 in response to swinging of the left-hand or first door 21 by operating the handle 56 so that the two doors are opened and closed together. An endless chain engaging around both of the sprockets 58 was found to be inoperative after a self-cleaning cycle because the high temperatures encountered resulted in binding of the parts. For this reason, the adjustable solid links 61-63 were added with the springs 65 compensating for heat expansions and contractions of the chains 59 and insuring proper engagement thereof with their respective sprockets at all times.

Means also are provided as part of such door swinging means for releasably maintaining the doors in selectively adjusted positions, i.e., fully closed, partially opened or fully opened. This means comprises a cam disc 66 mounted upon and secured to the lower end portion of the pintle 57 of the left-hand door 21 below the sprocket 58. As shown in FIG. 8, this cam disc is provided with three peripherally spaced notches 67, 68 and 69. A vertically extending pin or roller 71 on the forward end of a cam follower lever 72 cooperates with the edge notches in the cam disc 66. The lever 72 is pivotally mounted in any suitable manner at its inner end at 73 to the frame of the oven (FIG. 6) and a spring 74 is connected at its inner end in any desired manner to the oven and at its outer end to the forward portion of the lever 72 to resiliently and releasably maintain the pin or roller '71 in edge engagement with the cam disc 66.

With the doors 21 closed, this cam follower pin 71 is held against the forward surface of the notch'67 to maintain the doors in closed position. The notch 67 is so shaped as to cooperate with the pin 71 under the acl060 l 2 MR6 tion of the spring 74 to cammingly complete a door closing operation when the doors have been moved close to a closed position. Swinging of the doors 21 outwardly to a partially open position in which they extend substantially parallel to the sides of the oven will result in the cam disc 66 being rotated to dispose its notch 68 in alignment with the pin 71. The spring 74 and cam follower 71, 72 thus will function to releasably maintain the doors in that partially opened position. Likewise, further swinging of the doors 21 to fully opened position will align the third notch 69 of the cam disc 66 with the pin 71 to releasably maintain the doors in that selected position.

Means also are provided for automatically locking the doors 21 in closed position during a self-cleaning cycle of operations. This means comprises a normally inoperative keeper or door lock 75 (FIG. 6) pivotally mounted on the oven frame intermediate its ends with its upper end adapted to be swung into operative engagement with a suitable pin 76 depending from the left-hand door 21 to prevent opening thereof. That lower end of the keeper 75 is connected by a link 77 to a bell crank 78 pivoted on the oven frame, which in turn is connected to the vertically disposed armature of a solenoid 79. When the latter is energized, the link 77 is pulled to the right in FIG. 6 to swing the upper end of the keeper 75 into operative position in engagement with the pin 76. The doors 21 thus are locked in closed position whenever the solenoid 79 is energized. Whenever the solenoid 79 is deenergized, a spring 81 (FIG. 2) connected to the bell crank 78 adjacent the connection thereof with the link 77 and on the opposite side of the bell crank pivot from the point of attachment of the solenoid armature returns the latter and the link 77 and keeper 75 to normal inoperative position, as shown in FIG. 6.

An oven cleaning control which comprises one of the control means 26 causes energization of the solenoid 79 when it is actuated manually to initiate a cleaning operation. The locking of the oven doors 21 in closed position thus is effected and they are maintained locked throughout a cleaning operation. At the completion thereof a'high temperature thermostat 82 (FIG. 2) which is mounted interiorly of the oven in well-known manner automatically deenergizes the solenoid 79 when the oven temperature falls below 580 F. to permit the spring 81 to swing the keeper 75 back to its normal inoperative position of FIG. 6. By this arrangement, the doors 21 which normally can be swung open at any time will be locked closed whenever the temperature of the oven is above normal maximum cooking temperature.

It is thought that the invention and many of the attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

We claim:

1. In a self-cleaning oven having a doublewalled construction of inner and outer top, bottom, rear and side walls defining interconnecting rear, bottom and side wall spaces, front door means, control means mounted in a side wall space, means for directing air into the latter said side wall space and to the lower exterior of said front door means from said bottom wall space, blower means comprising a cooling fan and rear duct means mounted in said rear wall space for drawing in ambient air and forcing the same forwardly through said bottom wall space and through said side wall spaces to direct cooling air upwardly over said front door means and said control means, and a motor for said fan mounted on said rear wall.

2. In a self-cleaning oven according to claim 1, shroud means mounted on said outer rear wall for requiring air drawn in by said cooling fan to pass in close proximity to said motor.

3. A self-cleaning oven according to claim 2, wherein said blower means includes a second inner fan mounted coaxially with said cooling fan interiorly of the oven, and plate means mounted on adjacent ends of said fans and interconnected by peripherally spaced spacers to drivingly support said inner fan on said cooling fan and prevent direct transfer of heat from said inner fan to the shaft of said motor.

4. In a self-cleaning oven according to claim 3, side air ducts mounted in the lower ends of said side wall spaces for directing cooling air from said rear air duct means over said front door means and having apertures in their upper walls for supplying cooling air to said side wall spaces and said control means.

5. In a self-cleaning oven according to claim 4, burner means disposed between said inner and outer bottom walls, and deflector means extending laterally upwardly from and forming a part of said outer bottom wall for protecting said side air ducts from the heat generated by said burner means.

6. A self-cleaning oven according to claim 1, wherein said front door means comprises a pair of interengaging doors mounted on vertical pintles and a handle attached to a first of one of said doors, means for swinging the second said door in response to swinging of said first door by aid handle, comprising sprockets mounted on the lower ends of the door pintles, chain means drivingly engaging said sprockets and including adjustable solid links, and a spring interconnected between said side walls and each of said solid links.

7. In a self-cleaning oven according to claim 6, a cam disc mounted on the lower end of the pintle of said first door having peripherally spaced notches, and a cam follower resiliently urged into engagement with said notches to releasably maintain said doors in selectively adjusted positions.

8. A self-cleaning oven according to claim 7, wherein one of said cam notches is so disposed as to function as a camming surface against which said cam follower exerts a door-closing force on the pintle of said first door.

9. In a self-cleaning oven according to claim 1, a normally inoperative door lock for said front door means, an oven cleaning control comprising one of said control means, and means operable by said oven cleaning control for moving said lock to operative position to prevent opening of said front door means whenever the temperature of said oven is above normal maximum cooking temperature, wherein said door locking means comprises a keeper, spring means urging said keeper to an inoperative position, a solenoid having an armature connected to said keeper, and a high temperature ther- 

1. In a self-cleaning oven having a double-walled construction of inner and outer top, bottom, rear and side walls defining interconnecting rear, bottom and side wall spaces, front door means, control means mounted in a side wall space, means for directing air into the latter said side wall space and to the lower exterior of said front door means from said bottom wall space, blower means comprising a cooling fan and rear duct means mounted in said rear wall space for drawing in ambient air and forcing the same forwardly through said bottom wall space and through said side wall spaces to direct cooling air upwardly over said front door means and said control means, and a motor for said fan mounted on said rear wall.
 2. In a self-cleaning oven according to claim 1, shroud means mounted on said outer rear wall for requiring air drawn in by said cooling fan to pass in close proximity to said motor.
 3. A self-cleaning oven according to claim 2, wherein said blower means includes a second inner fan mounted coaxially with said cooling fan interiorly of the oven, and plate means mounted on adjacent ends of said fans and interconnected by peripherally spaced spacers to drivingly support said inner fan on said cooling fan and prevent direct transfer of heat from said inner fan to the shaft of said motor.
 4. In a self-cleaning oven according to claim 3, side air ducts mounted in the lower ends of said side wall spaces for directing cooling air from said rear air duct means over said front door means and having apertures in their upper walls for supplying cooling air to said side wall spaces and said control means.
 5. In a self-cleaning oven according to claim 4, burner means disposed between said inner and outer bottom walls, and deflector means extending laterally upwardly from and forming a part of said outer bottom wall for protectiNg said side air ducts from the heat generated by said burner means.
 6. A self-cleaning oven according to claim 1, wherein said front door means comprises a pair of interengaging doors mounted on vertical pintles and a handle attached to a first of one of said doors, means for swinging the second said door in response to swinging of said first door by aid handle, comprising sprockets mounted on the lower ends of the door pintles, chain means drivingly engaging said sprockets and including adjustable solid links, and a spring interconnected between said side walls and each of said solid links.
 7. In a self-cleaning oven according to claim 6, a cam disc mounted on the lower end of the pintle of said first door having peripherally spaced notches, and a cam follower resiliently urged into engagement with said notches to releasably maintain said doors in selectively adjusted positions.
 8. A self-cleaning oven according to claim 7, wherein one of said cam notches is so disposed as to function as a camming surface against which said cam follower exerts a door-closing force on the pintle of said first door.
 9. In a self-cleaning oven according to claim 1, a normally inoperative door lock for said front door means, an oven cleaning control comprising one of said control means, and means operable by said oven cleaning control for moving said lock to operative position to prevent opening of said front door means whenever the temperature of said oven is above normal maximum cooking temperature, wherein said door locking means comprises a keeper, spring means urging said keeper to an inoperative position, a solenoid having an armature connected to said keeper, and a high temperature thermostat operable to cause deenergization of said solenoid to move said keeper into normal inoperative position. 